Centrifugal electrical circuit interrupting device



g- 5, 5 F. R. NEAL 2,846,540

CENTRIFUGAL ELECTRICAL CIRCUIT INTERRUPTING DEVICE Filed Dec. 6, 1954 W ATTORNEY United States Patent CENTRIFUGAL ELECTRICAL CIRCUIT INTERRUPTING DEVICE Frederick R. Neal, Darien, Conn., assignor to Electric Specialty Company, Stamford, Conn., a corporation of Delaware Application December 6, 1954, Serial No. 473,089

8 Claims. (Cl. 20080) This invention relates to a centrifugal electrical circuitrnterrupting device, and has for an object to provide a simple and effective means to interrupt an electrical circuit at a predetermined speed of a rotating member, such, for example, as a shaft or other member.

A further object is to provide a device of this character in which the circuit is automatically restored and the various elements are returned to their normal or retracted positions when the speed of the rotating shaft, for example, is reduced below a certain limit.

With the foregoing and other objects in view, I have devised the construction illustrated in the accompanying drawing forming a part of this specification. It is, however, to be understood the invention is not limited to the specific details of construction and arrangement shown, but may embody various changes and modifications within the scope of the invention.

In this drawing:

Fig. 1 is a transverse section substantially on line 1-1 of Fig. 2;

Fig. 2 is a longitudinal section of one half of the device;

Fig. 3 is a transverse section substantially on line 3--3 of Fig. 2, and

Fig. 4 is a detail section substantially on line 4--4 of Fig. 2.

The device comprises a rotating element construction including in the construction shown a shaft which may be the shaft of a motor or other machine, and a supporting element or plate 11 mounted to rotate with the shaft. In the arrangement shown it is mounted on a sleeve 12 keyed to the shaft to rotate therewith, as indicated at 13, and the supporting element 11 is keyed to the sleeve as indicated at 14. Mounted on the plate or supporting element 11 is a plurality of spring-loaded flyweights 15.- In the present case there are three of these weights equally positioned about the axis of the shaft 10 and each pivoted to the plate 11 by any suitable means, such, for example, as the stud or bolt 16, and held spaced from the support 11 by a washer 9 for clearance. Each fiyweight is an angular shaped member comprising an outer arm 17 and an inner radially extending arm 18, and they are each normally held in the retracted position as shown in Figs. 2 and 3, by a spring 19 secured at one end to the plate 11, as indicated at 20, and at its other end, as indicated at 21,.to the arm 18. This spring is a tension spring normally stressed to tend to swing the associated flyweight in a clockwise direction as viewed in Fig. 3 about its pivot 16, which movement is limited by a suitable stop 22 on the member 11 against which the arm 17 may rest.

Also mounted on the sleeve 12 and therefore on the shaft 10 is a switch-actuating collar or operating member 23. This collar is also spring-loaded by a coil spring 24 on the sleeve resting at one end against the fiange 25 of the sleeve and at its other end against the collar 23. This collar is free to slide on the sleeve longitudinally of the shaft toward and from the flyweight support 11 and therefore the flyweights thereon, but is secured to rotate with the shaft and sleeve 12 by any suitable means, such, for example, as a pin 26 carried by the sleeve with its head in a longitudinal channel or slot 27 in the sleeve. The outer end of the collar is flanged as shown at 28 to engage the inner ends of the arms 18 of the fiyweights, and at its opposite end has a tapered or inclined flange 29 adapted to engage the tapered inner ends 3i) of a series of operating buttons 31 for a series of switches 32.

In the arrangement shown these switches are mounted on a stationary support or plate 33 which may be mounted on the housing or frame of the machine 55 by screws 56, or be held in the position shown by other means, each switch being mounted on an insulating support or bracket 34 secured to the plate by any suitable means, such, for example, as the screws 35. This bracket has an arm 37 and on the arm is mounted a supporting conductor bar 38 by any suitable means, such, for example, as the screws 39. The switch operating button 31 is mounted to slide in this bar 38 and has an enlarged head 40 to limit its inward movement. This button is made of insulating material, such, for example, as nylon. At the free end of the bar 38 is mounted a yieldable spring stationary switch contact 41 by any suitable means such as the rivets 42. This yieldable contact spring is an important feature in this device, particularly for certain applications where the unit is subject to high shock. Associated with this contact 41 is a movable spring contact 43 mounted on a flat spring arm or conductor strip 44 secured to arm 37 on the insulating block 34 with a conductor bar 45 so that the spring 44 and bar 45 are electrically connected. They are insulated from bar 38 by the insulating strip 36 held between them by pressure of screws 39. Means is provided for connecting conductor wires of an electric circuit to be controlled to the bars 38 and 45 and thus to the switch contacts 41 and 43. They are shown in Fig. 1 at 46 and 47 connected by binding screws 48 and 49 to the bars 38 and 45 respectively.

The outer arms 17 of the flyweights are provided with means for securing one or more small weights to these arms to determine the speed of the member 11 which will cause centrifugal action and throw them outwardly to the released or dotted line position shown at the top of Fig. 3. This may be a screw 50 securing one or more weights 51 to the arm, or if preferred some means could be provided for adjusting the tension of the springs 19, or springs 19 of different tensions could be used. The free end of the other arm 18 of each fiyweight is provided with an inclined cam surface 52 on its inner side in position to cooperate with flange 28 on the end of the sleeve 23.

In operation, when the rotating shaft and elements 11 and 12, together with the flyweights, reach a predetermined speed, which may be determined or adjusted either by varying the strength of the springs 19 or by the addition or removal of weights 51 held by the screws 50, centrifugal force will overcome the retarding effect or force of the springs 19, together with friction on mountings of the flyweights and the pressure of the sleeve 23 against them, and these flyweights will then throw out suddenly to the dotted line position shown at the top of Fig. 3 (only one of these elements being shown in this position to simplify the drawing), allowing the switchactuating collar 23 to be shifted forwardly (or to the left as viewed in Fig. 2) by spring 24 toward the flyweight frame or support 11. As this collar travels forwardly its inclined flange 29 will engage the inner ends 30 of the contact spring actuating buttons 31, shifting them axially or outwardly, and each button will shift the associated movable contact 43 outwardly to separate it from the contact 41 and open the circuit in which these contacts are located, this action being effected by the head 40 of the button 31 engaging the flexible spring strip 44 and forcing it outwardly.

When the speed of the shaft and the member 11 with the fiyweights has dropped sufficiently, the force of the springs 19 upon the fiyweights causes them to retract or move to the full line position of Fig. 3, this movement being limited by the arms 17 engaging the stops 22. During this movement the inclined 'cam surfaces 52 on the arms 18 of the flyweights engage the outer flanged end 28 of the collar 23 and push the collar 23 backwardly to its retracted position, or that is, to the right as viewed in Fig. 2, against the action of the spring 24. This movement of the collar releases the pressure on the switch operating buttons 31 and permits them to be forced inwardly by the spring action of the spring strips 44 carrying the movable contacts 43, permitting the contacts 43 to again engage the contacts 41 and close their respective circuits.

The operating parts may be enclosed in and protected by a suitable cover 53 secured to member 33 by any suitable means such as screws 54.

It will be seen the flyweights all act independently and thus all of them must throw outwardly in order that the collar 23 may be shifted from its retracted position of Fig. 2 by the spring 24. The switches may be connected in difierent arangements, but they are normally connected in parallel in the circuit to be controlled and therefore all of them must open to break this circuit. That is, as long as one switch remains closed the circuit will not be interrupted. The collar 23 is held in its retracted position by engagement of its outer end or flange 28 against the flat surfaces 57 (Fig. 4) on the rear side of the fiyweights.

It will be seen that this is a very simple and effective means and arrangement for automatically opening or interrupting an electric circuit when the speed of a rotating element, such as a shaft, for example, reaches a certain limit, and that the elements are all automatically returned to their normal or retracted positions to close or restore the circuit when the speed drops below a certain predetermined limit. Although this unit is shown and described, by way of example and disclosure purposes, as mounted on the housing or frame and shaft of a machine, it will be understood it may be mounted by different means. For example, it may be furnished as a self-contained unit between its own bearings and coupled to another machine. An important use for this device is on equipment supplied to the Navy where this equipment is subjected to Class HI shock test.

It is also to be understood that, although this unit has been shown and described as an interrupter for an electric circuit, it can be used as a circuit closing device. For this purpose the contacts 41 and 43 could be normally separated and the movable contact shifted to engagement with the other by the button 31.

Having thus set forth the nature of my invention, I claim:

1. In a circuit controlling device of the character described, a rotatable shaft, a support secured on the shaft, a spring loaded flyweight pivotally mounted on the support adapted to shift outwardly from a normally retracted position by centrifugal action as the speed of the shaft reaches a given limit, a spring loaded collar mounted to slide longitudinally of the shaft toward and from the said support and normally held in the retracted position by the flyweight when it is in the retracted position, a stationary support, at least one electric switch mounted on the stationary support including a movable contact, a shiftable operating member for shifting the contact, cam means carried by the collar for shifting said operating member by movement of the collar from its retracted toward the advanced position upon its release by outward movement of the flyweight, and cam '4 means on the flyweight to shift the collar to the retracted position by movement of the flyweight from its outward to its retracted position.

2. In a circuit controlling device of the character described, a rotatable shaft, a support mounted on and secured to the shaft, spring loaded flyweights pivotally mounted on the support adapted to shift outwardly from normally retracted positions by centrifugal force as the speed of the shaft reaches a certain limit, a stationary support, electric switches mounted on the stationary support including movable contacts, movable operating members for shifting the contacts, an operating collar mounted to slide longitudinally of the shaft and held in a normally retracted position by the flyweights while in their retracted positions, a spring tending to move the collar forwardly from its retracted position toward the flyweights, said collar provided with an inclined cam surface to shift said operating members to operate the switch contacts by forward movement of the collar upon its release by outward movement of the flyweights, and cam means on the fiyweights to shift the collar backwardly to its retracted position by movement of the flyweights to their retracted positions upon reduction of the speed of the shaft below a given limit.

3. In a circuit controlling device of the character described, a rotatable shaft, a support mounted on and secured to the shaft, a spring loaded fiyweight pivotally mounted on the support adapted to shift outwardly from a normally retracted position by centrifugal force as the speed of the shaft reaches a certain limit, a stationary support, an electric switch mounted on the stationary support including a conductor bar, a stationary contact mounted on the bar, a movable spring contact movable to and from engagement with the first contact, an operating button carried by the bar and movable to shift the movable contact, an operating collar mounted to slide longitudinally of the shaft and normally held in a retracted position by the flyweight when in its retracted position, a spring tending to shift the collar forwardly from its retracted position, and said collar provided with an inclined cam surface to shift the operating button to operate the movable contact on release of the collar by the flyweight.

4. In a circuit controlling device of the character described, a rotatable shaft, a support mounted on and secured to the shaft, a spring loaded flyweight pivotally mounted on the support adapted to shift outwardly from a normally retracted position by centrifugal force as the speed of the shaft reaches a certain limit, a stationary support, an electric switch mounted on the stationary support including a conductor bar, a stationary contact mounted on the bar including a spring conductor strip and a contact element carried by said strip spaced from the bar, a movable spring contact movable to and from engagement with the first contact, operable means carried by the bar to shift the movable contact, an operating collar mounted to slide longitudinally of the shaft and normally held in retracted position by the fiyweight, a spring tending to shift the collar forwardly from its retracted position, and said collar provided with means to operate said operable means to shift the movable contact.

5. In a circuit controlling device of the character described, a rotatable shaft, a supporting member mounted on the shaft to rotate therewith, a plurality of spring loaded flyweights mounted on the supporting member adapted to swing outwardly under centrifugal force when the speed of the member reaches a given limit, said fiyweights mounted to act independently of each other with separate retracting springs, a spring loaded collar slidable longitudinally of the shaft held in a retracted position against action of its spring by the fiyweights in their retracted positions and releasable by outward movement of the fiyweights, a stationary support, cooperating stationary and movable switch contacts mounted on said support, means operable by movement of the collar from its retracted position upon its release by outward movement of the flyweights to shift the movable contacts relative to the stationary contacts, and cooperating means on the flyweights and collar to shift the collar to its retracted position against action of its spring as the flyweights are retracted by their springs when the speed of the shaft drops to a given limit comprising inclined cam surfaces on the flyweights engaging the collar.

6. In a circuit controlling device of the character described, a rotatable support, a plurality of spring loaded flyweights pivotally mounted on the support adapted to swing outwardly under centrifugal force against action of their springs when the speed of the support reaches a given limit, said flyweights mounted to act independently of each other against separate retracting springs, a spring loaded collar movable toward the support under action of its spring normally held in retracted position by the flyweights in their retracted positions and releasable by outward movement of the flyweights, a stationary support, electrical switches mounted on the stationary support each including relatively movable contacts, means operable by movement of the collar from its retracted position by action of its spring to shift said contacts comprising an inclined cam surface on the collar and switch shifting means operable thereby, and cooperating means on the flyweights and collar to shift the collar to its retracted position against action of its spring by movement of the flyweights under action of their springs to their retracted positions.

7. In a circuit controlling device of the character described, a rotatable support, a plurality of spring loaded flyweights pivotally mounted on the support adapted to swing outwardly independently of each other under centrifugal force against action of separate springs when the speed of the support reaches a given limit, a spring loaded collar movable toward the support under action of its spring normally held in retracted position against action of its spring by the flyweights in their retracted positions and releasable by outward movement of the flyweights, a stationary support, electrical switches mounted on the stationary support each including movable contacts, and

shiftable means operable by movement of the collar from its retracted position under action of its spring upon release by the flyweights to shift said contacts comprising an inclined cam surface on the collar engaging said shiftable means.

8. In a circuit controlling device of the character described, a rotatable shaft, a support mounted on the shaft to rotate therewith, three flyweights mounted equally spaced about the shaft on the support, means mounting the flyweights to shift outwardly away from the shaft under centrifugal force when the speed of the shaft reaches a given limit, a separate spring for each fiyweight tending to shift it to a retracted position, a collar slidable longitudinally of the shaft between a retracted and a forward position, a spring tending to shift the collar from the retracted to the forward position, the flyweights positioned when in their retracted positions to retain the collar in its retracted position and each provided with an inclined cam surface to engage the collar and shift it longitudinally of the shaft to its retracted position as the flyweights move at right angles to the shaft to their retracted positions under action of their spring, a stationary support, a plurality of switches on said latter support one for each flyweight, an actuating member for each switch movable in a direction perpendicular to the shaft, and said collar provided with an inclined cam surface to shift the switch actuating members outwardly away from the shaft by forward movement of the collar under action of its spring when the collar is released by outward movement of the flyweights under centrifugal action.

References Cited in the file of this patent UNITED STATES PATENTS 2,083,343 Naul June 8, 1937 2,144,733 Jeppsson Jan. 24, 1939 2,372,064 Esarey Mar. 20, 1945 2,419,141 Johns et al. Apr. 15, 1947 2,493,140 Heath Jan. 3, 1950 2,614,161 Bailey et al. Oct. 14, 1952 2,708,696 Leitner et al. May 17, 1955 

